A nootropic is a substance that is believed to enhance cognitive functions such as memory, creativity, and motivation. These compounds can be natural or synthetic and are often used by students, professionals, and others looking to improve their mental performance. Common examples of nootropics include caffeine, ginkgo biloba, and modafinil. While some nootropics are available over-the-counter, others may require a prescription. The effectiveness and safety of these substances can vary widely, and research on their long-term effects is still ongoing. It's important to approach nootropics with caution and consult a healthcare professional before use.